Breakdown of Warum bist du durch den Flur gerannt?
sein
to be
du
you (informal singular)
rennen
to run
warum
why
Questions & Answers about Warum bist du durch den Flur gerannt?
Why is it den Flur and not der Flur?
The preposition durch (through) always requires the accusative case. Since Flur (hallway) is a masculine noun (der Flur), the article changes to den in the accusative.
Why does this sentence use bist instead of hast for the past tense?
In German, the spoken past tense normally uses haben (to have) as the helper verb. However, verbs that show movement from one place to another, like rennen (to run), use sein (to be) instead. That is why we use bist here.
What is the infinitive form of gerannt?
The infinitive is rennen (to run). It is what we call a mixed verb: it changes its middle vowel like a strong/irregular verb (e to a) but still takes the standard -t ending of a weak/regular verb instead of -en.
Why is gerannt at the very end of the sentence?
This is the standard word order for the conversational past tense (Perfekt). The helper verb (bist) takes the second position after the question word (Warum), and the main action verb (gerannt) gets pushed to the very end of the sentence.